Washer pump

ABSTRACT

Since the pump chamber ( 32   a ), the valve chambers ( 33   a  and  33   b ), the discharge holes ( 33   e  and  33   f ), and the flow paths ( 34  and  35 ) are integrally provided to each other in the housing ( 30 ), in the case where these are formed of separate members, a step or the like that inhibits the flow of the cleaning liquid “W” is not formed in the flow path of the cleaning liquid “W”, so that the pressure loss of the cleaning liquid “W” can be reduced. In addition, since the valve chambers ( 33   a  and  33   b ) of the flow paths ( 34  and  35 ) extend to the discharge holes ( 33   e  and  33   f ), the cleaning liquid “W” flowing out of the flow paths ( 34  and  35 ) can be discharged at a portion closer to the central of the valve chambers ( 33   a  and  33   b ). As a result, the outlet portions of the flow paths ( 34  and  35 ) and the inlet portions of the discharge holes ( 33   e  and  33   f ) is brought closer to each other, and the turbulent of the cleaning liquid “W” in the valve chambers ( 33   a  and  33   b ) can be suppressed, thereby reducing the pressure loss.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Stage application of International PatentApplication No. PCT/JP2017/017386, filed on May 8, 2017, which claimspriority to Japanese Patent Application Numbers 2016-108822, filed onMay 31, 2016; 2016-112941, filed on Jun. 6, 2016; 2016-117091, filed onJun. 13, 2016; and 2016-117092, filed on Jun. 13, 2016, each of which ishereby incorporated by reference in its entirety.

TECHNICAL FIELD

The present invention relates to a washer pump configured to suck aliquid stored in a tank, and to jet the liquid onto an object to becleaned.

BACKGROUND ART

Windshields are respectively provided on the front-side and therear-side of a vehicle such as automotive vehicle, and washerapparatuses for cleaning the windshields are provided to predeterminedpositions in an engine-compartment. The washer apparatus includes awasher pump and a tank for storing a liquid. The washer pump is drivenby the operation of the operation switch, and injects a liquid in thetank to each of the windshields in accordance with the rotationdirection of the motor. Then, the liquid jetted to the windshield iswiped by the wiper blade by driving the wiper apparatus, whereby thewindshield (cleaning surface) is cleaned cleanly.

A washer pump for sucking a liquid stored in a tank, and jetting theliquid onto a cleaning surface includes, for example, a technicaldescribed in Japanese Patent Application Laid-Open Publication No.:JP2015-014347.

The washer pump described Japanese Patent Application Laid-OpenPublication No.: JP2015-014347 includes: a receiving chamber (pumpchamber) for receiving an impeller; first and second valve chambers(valve chambers) in which cleaning liquid (liquid) flows in accordancewith the rotation direction of the impeller; first and second passages(flow paths) for connecting the receiving chamber to the first andsecond valve chambers; a valve main body (switching valve) forseparating the first and second valve chambers from each other; andfirst and second liquid pipes (discharge holes) provided on both sidesof the moving direction of the valve main body.

SUMMARY

However, according to the washer pump described in Japanese PatentApplication Laid-Open Publication No.: JP2015-014347, the liquid flowsfrom the pump chamber toward the flow path by rotation of the impeller,and the liquid flowing into the flow path flows vigorously through theflow path. Then, the liquid flowing through the flow path is forcefullydischarged from the end portion of the valve chamber to the inside ofthe valve chamber. That is, the liquid discharged from the flow path israpidly diffused inside the valve chamber. The liquid discharged intothe valve chamber vigorously moves in all directions inside the valvechamber and becomes turbulent flow. Specifically, liquids collide witheach other. As a result, a pressure loss of the liquid occurs inside thevalve chamber, and a loss occurs in the flow of the liquid. Therefore,problems such as lowering of the injection ability of the washer pumpmay occur.

It is an object of the present invention to provide a washer pumpcapable of suppressing a decrease in the injection ability and furtherreducing the size and weight of the washer pump.

In one aspect of the present invention, there is provided a washer pumpconfigured to suck liquid stored in a tank and configured to jet theliquid to a surface to be cleaned, comprising: a motor that rotates inforward and reverse directions; an impeller rotated by the motor, a pumpchamber in which the impeller is housed; a pair of valve chambers inwhich the liquid flows in response to the rotation direction of theimpeller; a changeover valve for partitioning the pair of valvechambers; a pair of discharge holes provided on both sides of theswitching valve in the moving direction; and a pair of flow pathsprovided between the pump chamber and the pair of valve chambers,wherein the pump chamber, the valve chamber, the discharge hole, and theflow paths are integrally provided to each other in the housing, and theflow paths extend to the discharge hole on the same side as the valvechamber.

In another aspect of the present invention, the flow passage area on thesame side as the pump chamber of at least one of the flow paths issmaller than the flow passage area on the same side as the valvechamber.

In another aspect of the present invention, one of the flow paths has aninclined wall that gradually increases a flow passage area from the sameside as the pump chamber toward the same side as the valve chamber.

In another aspect of the present invention, one of the flow path has anopposing wall facing the inclined wall, the opposing wall is disposedparallel to the side wall of the housing near the side wall, theinclined wall is provided on the inside of the side wall of the housing.

In another aspect of the present invention, the flow passage area of oneof the flow path on the same side as the pump chamber is smaller thanthe flow passage area of the other of the flow paths on the same side asthe pump chamber.

In another aspect of the present invention, one of the flow paths isprovided corresponding to the injection of the liquid onto the surfaceon the front-side of the vehicle.

According to the present invention, since the pump chamber, the valvechamber, the discharge hole, and the flow path are integrally providedin the housing, in the case where these are formed of separate members,a step or the like that inhibits the flow of the liquid does not need tobe formed in the path through which the liquid flows, so that thepressure loss of the liquid can be reduced.

In addition, since the valve chamber side of the flow path extends tothe position of the discharge hole, the liquid flowing out of the flowpath can be discharged at a portion closer to the central of the valvechamber than before. As a result, the outlet portion of the flow pathand the inlet portion of the discharge hole can be brought close to eachother, and turbulent of the liquid inside the valve chamber can besuppressed, so that pressure loss can be reduced.

Therefore, the lowering of the injection capability is suppressed, andin the washer pump having the same injection capability as in the past,it is possible to adopt a small motor having a low output, and it ispossible to realize further size and weight reduction of the washerpump.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view showing a washer pump accordingto the present invention, which is installed on a washer tank;

FIG. 2 is a perspective view showing the washer pump of FIG. 1 from thesame side as the motor cover;

FIG. 3 is a perspective view showing the washer pump of FIG. 1 from thesame side as the cover member;

FIG. 4 is a cross-sectional view of the washer pump taken along an axisof the armature shaft;

FIGS. 5(a) and 5(b) are perspective views each showing a fixed structureof the magnet to the motor accommodating portion;

FIG. 6 is a cross-sectional view of the motor accommodating portiontaken in a direction intersecting the axis of the armature shaft;

FIG. 7 is a cross-sectional view of the commutator taken along the lineA-A of FIG. 4;

FIG. 8 is a cross-sectional view of the armature core taken along theline B-B of FIG. 4;

FIG. 9 is an explanatory view showing a brush structure mounted on aninside of a motor cover;

FIG. 10 is a plan view showing a pump chamber (with a cover memberomitted) of the washer pump;

FIG. 11 is an enlarged view showing a portion surrounded by the dashedcircle “C” of FIG. 4;

FIG. 12 is a perspective view showing a detailed structure of animpeller;

FIGS. 13(a) and 13(b) are cross-sectional views each showing theposition of the discharge hole with respect to the opening of the valvechamber;

FIGS. 14(a) and 14(b) are perspective views each showing the valve unit;

FIG. 15 is a cross-sectional view taken along the line D-D of FIG.14(a);

FIG. 16 is a cross-sectional view of a housing taken along the line E-Eof FIG. 10;

FIG. 17 is a partial enlarged view showing a portion surrounded by thedashed circle “F” of FIG. 10;

FIG. 18 is a partially enlarged cross-sectional view showing amodification of the porous filter;

FIG. 19 is an explanatory view of the flow of cleaning liquid on thefront-side; and

FIG. 20 is an explanatory view of the flow of cleaning liquid on therear-side.

DETAILED DESCRIPTION

Hereinafter, an embodiment of the present invention will be described indetail with reference to the drawings.

FIG. 1 is an exploded perspective view showing a washer pump of thepresent invention, which is installed on a washer tank.

As shown in FIG. 1, the washer tank (tank) 10 is formed into a hollowsubstantially rectangular parallelepiped shape from white andtranslucent plastic material or the like, and cleaning liquid (liquid)“W” such as washer liquid is stored in the washer tank. The washer tank10 includes a tank wall 12 forming the washer tank 10, and a pumpmounting portion 13 is integrally provided to the bottom of the tankwall 12. The pump mounting portion 13 is provided to a recessed portionof the washer tank 10, and the pump mounting portion 13 is provided witha pair of tank side retaining portions 14 for retaining the housing 30of the washer pump 20. Each of the tank-side retaining portions 14 isprovided by radially inwardly projecting part of the pump mountingportion 13, and the distance between the tank-side retaining portions 14is set to W1.

The bottom of the pump mounting portion 13 is provided with an insertionhole 15 into which the suction pipe 32 c of the washer pump 20 isinserted. A grommet 16 formed into an annular shape and formed ofelastic material such as rubber is mounted in the insertion hole 15. Thegrommet 16 is elastically deformed between the washer tank 10 and theintake pipe 32 c, and configured to seal a gap between the insertionhole 15 and the suction pipe 32 c. As a result, the cleaning liquid “W”is prevented from being leaked from a gap between the washer tank 10 andthe washer pump 20, and the washer pump 20 is prevented from beingaccidentally lumberingly moved with respect to the washer tank 10.

Note that, since the pump mounting portion 13 is composed of a recessedportion of the washer tank 10, most of the washer pump 20 is received inthe pump mounting portion 13 with the suction pipe 32 c inserted intothe insertion hole 15 and the housing 30 held by each tank sideretaining portion 14, that is, with the washer pump 20 assembled to thewasher tank 10. Therefore, the washer pump 20 does not protrude greatlyfrom the washer tank 10. Therefore, the washer tank 10 and the washerpump 20 (washer apparatus) can be easily installed in anengine-compartment (not shown) of a vehicle such as automotive vehicle.As shown in FIG. 1, the washer apparatus is installed in theengine-compartment with the pump mounting portion 13 located on lowerside of the washer tank 10.

FIG. 2 is a perspective view showing the washer pump of FIG. 1 from thesame side as the motor cover, FIG. 3 is a perspective view showing thewasher pump of FIG. 1 from the same side as the cover member, and FIG. 4is a cross-sectional view of the washer pump taken along the axialdirection of the armature shaft.

As shown in FIGS. 2 to 4, the washer pump 20 includes a housing 30 whichis formed so as to have a substantially T-shaped cross section byinjection molding or the like of resin material such as plastic. Amongcomponents constituting the washer pump 20, the housing 30 is a largecomponent, and forms an outline of the washer pump 20. In other words,by reducing the size of the housing 30, it is possible to realize thewasher pump 20 improved in size. The housing 30 includes: a motoraccommodating portion 31, a pump accommodating portion 32, and a valvebody accommodating portion 33.

FIGS. 5(a) and 5(b) are perspective views each showing a fixingstructure of the magnet to the motor accommodating portion, and FIG. 6is a cross-sectional view of the motor accommodating portion along adirection intersecting with the axial direction of the armature shaft,respectively.

As shown in FIGS. 2 to 6, the motor accommodating portion 31 is formedinto a generally cylindrical shape, and formed with a motor chamber 31 ain which the motor 40 is accommodated, and which is positioned on theinside of the motor accommodating portion 31 in the radial directionthereof. A plurality of support ribs 31 b is provided on the inside ofthe yoke 41 in the radial direction thereof, which forms part of themotor 40, and configured to support the outside of the yoke 41. Thesupport ribs 31 b also serve to reinforce the motor accommodatingportion 31. Each of the support ribs 31 b extends in the axial directionof the motor accommodating portion 31, and they are disposed atpredetermined intervals in the circumferential direction of the motoraccommodating portion 31. As a result, it is possible to suppress themotor 40 from being accidentally moved and rattled in the motoraccommodating portion 31 without making it difficult to mount the motor40 to the motor accommodating portion 31.

Furthermore, as shown in FIG. 6, a pair of rib groups RB composed ofthree reinforcing ribs 31 c is provided on the outside of the motoraccommodating portion 31 in the radial direction thereof, that is, onthe outer circumference portion. These rib groups RB are provided forthe downsizing (and thinning) of the motor accommodating portion 31, andserve to reinforce the motor accommodating portion 31. A total of sixreinforcing ribs 31 c extend in the axial direction of the motoraccommodating portion 31, similarly to the supporting ribs 31 b providedon the inside of the motor accommodating portion 31 in the radialdirection thereof. The pair of rib groups RB is arranged at intervals ofapproximately 180 degrees so as to face each other about the axialcenter of the motor accommodating portion 31. In addition, among thereinforcing ribs 31 c forming each rib group RB, the separationdimension of the apexes of the reinforcing ribs 31 c that are thefarthest apart from each other is set to W2.

Note that the motor accommodating portion 31 of the housing 30 is aportion to be held by each tank-side retaining portion 14 of the washertank 10. Specifically, a pair of reinforcing ribs 31 c each having aseparation dimension W2 is sandwiched between the tank-side retainingportions 14. That is, the separation dimension W2 of the top portions ofreinforcing ribs 31 c furthest away from each other is set to beslightly larger than the separation dimension W1 of the tank-sideretaining portions 14, i.e., W2 >W1. As a result, some of thereinforcing ribs 31 c also serves to fix the washer pump 20 to thewasher tank 10.

As shown in FIGS. 5(a) and 6, a magnet supporting portion 31 d isprovided on the inside of the motor accommodating portion 31 in theradial direction thereof. The magnet supporting portion 31 d is providedso as to protrude from the bottom portion BT of the motor accommodatingportion 31, and disposed on the inside of the motor accommodatingportion 31 in the radial direction thereof with a predetermined gap “S”.The magnet supporting portion 31 d is formed into a substantiallyarc-shaped cross section, and configured to support one end side (lowerside in FIG. 6) of the pair of magnets 42 in the width directionthereof, which forms part of the motor 40, on both sides (left and rightsides in FIG. 6) of the magnet supporting portion 31 d in the widthdirection thereof.

Furthermore, as shown in FIGS. 5(a), 5(b) and 6, a pair of magnetmounting portions 31 e is provided on the inside of the motoraccommodating portion 31 in the radial direction thereof. The magnetmounting portions 31 e are disposed at intervals of 180 degrees so as toface each other about the axial center of the motor accommodatingportion 31. Each of the magnet mounting portions 31 e is formed intosubstantially the same shape as the magnet supporting portion 31 d, andprovided so as to project from the bottom portion BT of the motoraccommodating portion 31 in the same manner as that of the magnetsupporting portion 31 d. Each of the magnet mounting portions 31 e isconfigured to support one end side of the pair of magnets 42 in theheight direction thereof, that is, on the lower side in FIG. 4.

Note that a first opening 31 f is formed on the opposite side from thebottom along the axial direction of the motor accommodating portion 31,that is, on the upper side in FIG. 4, and the first opening 31 f isclosed by the motor cover 50. That is, the motor chamber 31 a is closedby the motor cover 50. Furthermore, the motor cover 50 and the motoraccommodating portion 31 are closely attached to each other by adhesivemeans such as ultrasonic welding. Therefore, rainwater or the like doesnot enter the motor accommodating portion 31.

FIG. 7 shows a cross-sectional view of the commutator taken along theline A-A in FIG. 4, FIG. 8 shows a cross-sectional view of the armaturecore taken along the line B-B in FIG. 4, and FIG. 9 shows an explanatoryview explaining a brush structure mounted on the inside of the motorcover.

As shown in FIGS. 4 to 9, a motor 40 is accommodated in the motoraccommodating portion 31. Here, the motor 40 includes a motor cover 50that closes the first opening 31 f of the motor accommodating portion31. The motor 40 includes: a yoke 41 having a generally-cylindricalcross-section formed by pressing a steel plate or the like; and acut-off portion partially formed along its circumferential direction. Asshown in FIGS. 5(a), 5(b) and 6, the outside of the yoke 41 in theradial direction thereof is supported by the support ribs 31 b, and theyoke 41 enters the predetermined gap “5”. That is, the magnet supportingportion 31 d is radially disposed on the inside of the yoke 41.

Note that, as shown in FIG. 6, a notch 41 a extending in the axialdirection of the yoke 41 is formed, and a positioning protrusion 31 gformed on the inside of the motor accommodating portion 31 in the radialdirection thereof is inserted into the notch 41 a. As a result, the yoke41 is fixed with the yoke 41 positioned in the circumferential directionof the motor accommodating portion 31. Although not shown in detail, thepositioning and fixing of the yoke 41 in the axial direction of themotor accommodating portion 31 is performed by partially contacting thebottom portion BT of the motor accommodating portion 31 with one endside of the yoke 41 in the axial direction (the lower side in FIG. 4).In this manner, the yoke 41 (the motor 40) is fixed on the inside of themotor chamber 31 a.

Two (bipolar) magnets (permanent magnets) 42 are fixed to the inside ofthe yoke 41 in the radial direction thereof. Specifically, the inside ofone magnet 42 in the radial direction is magnetized to the “5” pole, andthe inside of the other magnet 42 in the radial direction is magnetizedto the “N” pole. Each of the magnets 42 is formed into a substantiallyarc-shaped cross section, and the outside of each magnet in the radialdirection thereof is placed in contact with and fixed to the inside ofthe yoke 41 in the radial direction thereof. That is, the yoke 41 formsa magnetic path through which the lines of magnetic force of the magnets42 pass.

Note that one end side of each magnet 42 in the height direction thereofis in contact with each magnet mounting portion 31 e, and one end sideof each magnet 42 in the width direction thereof is in contact with bothsides of the magnet supporting portion 31 d in the width directionthereof. On the other hand, as shown in FIGS. 5(a) and 5(b), the otherend side (upper side in FIG. 4) of each magnet 42 in the heightdirection thereof is supported by a plurality of support claws 41 bformed on the other side (upper side in FIG. 4) of the yoke 41 in theaxial direction thereof, and the other end side (upper side in FIG. 6)of each magnet 42 in the width direction thereof is elasticallysupported by a spring pin SP formed into a substantially U-shape. Thatis, each magnet 42 is pressed by the spring force of the spring pin SPagainst the yoke 41.

In this embodiment, the magnet 42 is fixed to the yoke 41 by one springpin SP and the magnet supporting portion 31 d without using two springpins SP. That is, since the magnet supporting portion 31 d is made ofnon-magnetic material, it does not disturb the magnetic path formed byeach magnet 42. Therefore, since each magnet 42 can be further reducedin size, the further reduction in size and weight of the washer pump 20can be achieved.

As shown in FIGS. 4, 7, and 8, an armature core 43 is rotatably providedon the inside of each magnet 42 in the radial direction thereof througha predetermined air gap. An armature shaft 44 is disposed on therotation center of the armature core 43, that is, the rotation center ofthe motor 40 so as to extend and penetrate through the motor 40. Thatis, the armature shaft 44 rotates together with the armature core 43.

One end side of the armature shaft 44 in the axial direction thereof isrotatably supported by a first bearing B1 mounted on the bottom portionBT of the motor accommodating portion 31, and the other end side of thearmature shaft 44 in the axial direction thereof is rotatably supportedby a second bearing B2 mounted on the motor cover 50.

In the vicinity of the armature core 43 on the other end side of thearmature shaft 44 in the axial direction thereof, a commutator 45 withwhich two power supply brushes 54 slidably contact is fixed. As shown inFIG. 7, the commutator 45 includes six segments (commutator pieces) 45 ain total, and the segments 45 a are arranged at equal intervals (60degrees) in the circumferential direction around the axial center of thearmature shaft 44. Furthermore, each segment 45 a is solidified bymolding resin MR so as to have a substantially cylindrical shape, andcoils 46 are hooked on respective hook portions FK of the segments 45 a.

The armature core 43 is formed into a substantially cylindrical shape bystacking a plurality of steel plates, and as shown in FIG. 8, a total ofsix slots 43 a are provided so as to correspond to the six segments 45a. In other words, the armature core 43 comprises a total of six teeth“T”. In each slot 43 a, the coil 46 is wound on the basis of theoverlapping winding method. Note that the “overlapping winding” means awinding method in which the coil 46 is wound about the armature shaft 44so as to form cross-coupled slots 43 a which are opposed to each other.That is, in this embodiment, by providing a total of six slots 43 a, themounting of the coil 46 to the armature core 43 can be completed inthree winding works by the double flyer method. Therefore, the timerequired for the winding operation can be shortened, and the cost can bereduced. For the coil 46, a copper wire (e.g., enameled wire) whoseouter periphery has been subjected to an insulating treatment is used.

As a result, the armature core 43 rotates in the forward and reversedirections at a predetermined number of revolutions in accordance withthe magnitude and orientation of the drive current supplied to each ofthe power supply brushes 54. One ends of the power supply terminals TM(see FIG. 9) are electrically connected to the respective power supplybrushes 54, and the other ends of the power supply terminals TMprotrudes into a connector connection 52 provided on the motor cover 50.

As shown in FIGS. 2 to 4 and 9, the motor cover 50 includes a cover mainbody 51 formed into a predetermined shape by resin material such asplastic, and formed into a substantially disk shape to close the firstopening 31 f of the motor accommodating portion 31. A connectorconnection portion 52 formed into a substantially box shape to which apower supply connector (not shown) on the vehicle side is mounted isprovided on the outside of the cover main body 51.

A second bearing B2 configured to rotatably support the armature shaft44 on the other end side in the axial direction is provided on theinside of the cover main body 51 and at the center thereof. A pair ofretaining plate fixing parts 51 a is provided on the inside of the covermain body 51, and opposed to each other at intervals of 180 degrees withrespect to the second bearing B2. These retaining plate fixing parts 51a are arranged in a radially outward portion of the cover main body 51,and the base end portion 53 a of the retaining plate 53 is fixed to eachretaining plate fixing portion 51 a without rattling. That is, the baseend portion 53 a of the retaining plate 53 is mounted on the inside ofthe cover main body 51.

Between each retaining plate fixing part 51 a of the cover main body 51and the connector connection pair of power supply terminals TM formedinto a bent shape are embedded by insert molding. Each power supplyterminal TM supplies a drive current from a power supply connector onthe vehicle to each power supply brush 54 via a pair of retaining plates53. That is, one end side of each power supply terminal TM iselectrically connected to each power supply brush 54 via each retainingplate 53. Note that, in the drawing on the left side of FIG. 9, eachretaining plate 53 and each power feeding brush 54 are shaded forclarity of illustration.

The retaining plates 53 are formed into the same shape, and formed bybending a long elastic member made of brass or the like into asubstantially V-shape. That is, each of the retaining plates 53 has aspring property. One side of the retaining plate 53 in the longitudinaldirection is provided with a base end portion 53 a fixed to theretaining plate fixing part 51 a, and the other side of the retainingplate 53 in the longitudinal direction is provided with a brushretaining portion (tip portion) 53 b for retaining a power supply brush54 formed into a substantially rectangular parallelepiped shape. Twobent portions 53 c are provided near the base end portion 53 a of thebrush retaining portion 53 b. That is, two bent portions 53 c areprovided in a portion near the base end portion 53 a along thelongitudinal direction of the retaining plate 53.

As described above, by providing the two bent portions 53 c to theretaining plate 53 so that they are disposed on the same side as thebase end portion 53 a of the retaining plate 53, as shown by theimaginary line in FIG. 9, the power feeding brushes 54 can be easilyarranged so as to face each other in a space-saving manner across thecommutator 45. In addition, by providing the two bent portions 53 c tothe retaining plate 53 so that they are disposed on the same side as thebase end portion 53 a of the retaining plate 53, each of the powerfeeding brushes 54 is in slidable contact with the commutator 45 with anoptimal pressing force. Furthermore, by providing the two bent portions53 c to the retaining plate 53 so that they are disposed on the sameside as the base end portion 53 a of the retaining plate 53, and bysetting the bending angle of the bent portion 53 c to an optimal value(approximately 90 degrees), the power supply brushes 54 are arranged inthe extending direction of the brush retaining portion 53 b beforeassembling the commutator 45, as shown in the right side of FIG. 9. As aresult, each of the power supply brushes 54 can be used up to the end.That is, each power supply brush 54 can be reduced in size, and fromthis point as well, it is advantageous to reduce the size and weight ofthe washer pump 20. As described above, the motor 40 of this embodimentemploys a two-pole, six-slot, two-brush electric motor.

Note that the present invention is not limited to two bent portions 53 cprovided in a portion closer to the base end portion 53 a along thelongitudinal direction of the retaining plate 53, and three or more bentportions may be provided. In this case, the pressing force or the likeof each power supply brush 54 against the commutator 45 can be adjustedmore finely.

As shown in FIG. 9, a honeycomb-shaped rib 55 is formed on the inside ofthe cover main body 51. The rib 55 protrudes from the cover main body 51toward the motor 40 at a predetermined height of about 1.0 mm, and isintegrally provided with the cover main body 51. The rib 55 is providedfor reinforcing the cover main body 51 in order to cope with thinning ofthe cover main body 51. When the power supply connector on the vehicleis plugged into and out of the connector connection portion 52, even ifa relatively large load acts on the cover main body 51, a sufficientintensity is obtained for the cover main body 51 by providing the rib 55to the cover main body 51.

FIG. 10 is a plan view showing the washer pump from the same side as thepump chamber (with the cover member omitted), FIG. 11 is an enlargedview of a portion surrounded by the dashed circle “C” of FIG. 4, andFIG. 12 is a perspective view showing the detailed structure of theimpeller.

As shown in FIGS. 4 and 10 to 12, an impeller 60 is rotatably fixed toone end side of the armature shaft 44 in the axial direction thereof.The impeller 60 and the armature shaft 44 are fixed by fitting in aso-called D-cut shape so that they cannot rotate relative to each other.That is, the impeller 60 is rotated by the motor 40. As shown in FIG.12, the impeller 60 includes: an impeller body 61 fixed to the armatureshaft 44; and a total of six vanes 62 extending radially from theimpeller body 61 and curved in a substantially crescent shape.

As shown in FIG. 11, bowl-shaped convex portions 62 a formed into an arcshape with a predetermined radius of curvature “R” are formed on thesame side of the six vanes 62 as the armature core 43 (on the same sideas a bowl-shaped recess 32 d) along the axial direction of the armatureshaft 44. The bowl-shaped convex portions 62 a are provided along thebowl-shaped recess 32 d of a pump chamber 32 a. Note that the radius ofcurvature of the bowl-shaped recess 32 d of the pump accommodatingportion 32 is set to “R”, whereby the impeller 60 faces the bowl-shapedrecess 32 d with a predetermined gap formed between the impeller 60 andthe bowl-shaped recess 32 d. As described above, by arranging twobowl-shaped recess 32 d the same in radius of curvature as each other sothat they extend along bowl-shaped convex portions 62 a, some axialdeviation of the impeller 60 with respect to the bowl-shaped recess 32 dis allowed, and their clearance is reduced to prevent deterioration ofthe pump capacity.

Furthermore, between the impeller body 61 and the six vanes 62, anannular flange portion 63 is formed. This flange portion 63 is disposedon the downstream side of the impeller main body 61 along the flowdirection of the cleaning liquid “W” (dashed arrow in FIG. 12). As aresult, as indicated by the dashed arrow in FIG. 12, the cleaning liquid“W” is promptly directed to the distal end of each vane 62, therebyimproving the pumping capacity.

As shown in FIGS. 4, 10, and 11, the pump accommodating portion 32includes a pump chamber 32 a and a cleaning liquid inflow hole 32 bprovided upstream of the pump chamber 32 a, i.e., on the washer tank 10.Note that the cleaning liquid inflow hole 32 b is formed into thesuction pipe 32 c , and inserted into the insertion hole 15 of thewasher tank 10. As shown in FIG. 4, the flow passage area of thecleaning liquid inflow hole 32 b is gradually decreased from the washertank 10 toward the pump chamber 32 a. As a result, the flow rate of thecleaning liquid “W” sucked into the cleaning liquid inflow hole 32 b isincreased, so that the cleaning liquid “W” can be efficiently suckedinto the pump chamber 32 a.

The pump chamber 32 a is formed into a flat shape in which the impeller60 is rotatably accommodated with a predetermined gap between them, andhas a bowl-shaped recess 32 d whose radius of curvature is set to “R”.The opening portions of the pump chamber 32 a and the valve chambers 33a and 33 b form a second opening 30 a of the housing 30, and the secondopening 30 a is closed by a cover member CV. The second opening 30 a isalso formed on the same side as a respiratory hole 80 of the housing 30,which will be described later. The portion of the second opening 30 awhere the respiratory hole 80 is provided is also closed by the covermember CV. Note that the cover member CV is formed into a substantiallyflat plate shape from resin material such as plastic, and firmly fixedto the housing 30 by ultrasonic welding or the like.

Furthermore, as shown in FIG. 4, an armature shaft 44 is disposed so asto cross the downstream side of the cleaning liquid inflow hole 32 b,that is, the same side as the pump chamber 32 a. Therefore, a lip sealLS made of rubber or the like is provided between the cleaning liquidinflow hole 32 b and the armature shaft 44. As a result, the cleaningliquid “W” flowing through the cleaning liquid inflow hole 32 b isprevented from leaking into the motor chamber 31 a.

Furthermore, when the polarity of the pair of power supply brushes 54 isreversed so as to rotate the motor 40 in the forward or reversedirections, the impeller 60 is also rotated in the forward or reversedirections inside the pump chamber 32 a. At this time, the cleaningliquid “W” flowing through the cleaning liquid inflow hole 32 b issucked into the pump chamber 32 a regardless of the rotation directionof the impeller 60.

FIGS. 13(a) and 13(b) show cross-sectional views each showing theposition of the discharge hole with respect to the opening of the valvechamber, FIGS. 14(a) and 14(b) show perspective views each showing thevalve unit, and FIG. 15 shows a cross-sectional view along the D-D lineof FIG. 14(a).

As shown in FIGS. 4, 10, and 13, the valve body accommodating portion 33includes a front-side valve chamber (valve chamber) 33 a and a rear-sidevalve chamber (valve chamber) 33 b which are disposed on the oppositeside of the pump chamber 32 a from the cleaning liquid inflow hole 32 b.That is, the cleaning liquid “W” discharged from the pump chamber 32 aflows into the pair of valve chambers 33 a and 33 b. In the valve bodyaccommodating portion 33, a front-side discharge pipe 33 c is integrallyprovided so as to correspond to the front-side valve chamber 33 a, and arear-side discharge pipe 33 d is integrally provided so as to correspondto the rear-side valve chamber 33 b.

The cleaning liquid “W” flowing into the front-side valve chamber 33 aflows out to the front-side discharge hole 33 e on the inside of thefront-side discharge pipe 33 c via the valve unit 70. The cleaningliquid “W” flowing into the rear-side valve chamber 33 b flows out tothe rear-side discharge hole 33 f on the inside of the rear-sidedischarge pipe 33 d via the valve unit 70. Note that the front-sidedischarge holes 33 e and the rear-side discharge holes 33 f constitute apair of discharge holes in the present invention.

As shown in FIG. 10, a front-side passage 34 is provided between thepump chamber 32 a and the front-side valve chamber 33 a. A rear-sidepassage 35 is provided between the pump chamber 32 a and the rear-sidevalve chamber 33 b. As described above, the motor accommodating portion31, the pump chamber 32 a, the pair of valve chambers 33 a and 33 b, thepair of discharge holes 33 e and 33 f, and the pair of flow paths 34 and35 are integrally provided in one housing 30. The cleaning liquid “W”flows into each of the valve chambers 33 a and 33 b in accordance withthe corresponding rotation direction of the impeller 60.

Specifically, by rotating the impeller 60 in the counterclockwisedirection, the cleaning liquid “W” flows from the pump chamber 32 atoward the front-side flow path 34. On the other hand, by rotating theimpeller 60 in the clockwise direction, the cleaning liquid “W” flowsfrom the pump chamber 32 a toward the rear-side flow path 35. Note thatsince each vane 62 of the impeller 60 is formed into a substantiallycrescent shape, the flow rate of the cleaning liquid “W” flowing outthrough the front-side flow path 34 is higher than that of the cleaningliquid “W” flowing out through the rear-side flow path 35 even if therotation speeds of the motor 40 in the forward and reverse directions isthe same as each other. Since the cleaning liquid “W” toward thefront-side windshield is affected by winds as compared with the cleaningliquid “W” toward the rear-side windshield, and it is necessary toincrease the injection pressure of the cleaning liquid “W”. That is, inthe washer pump 20 of this embodiment, the target position of thecleaning liquid “W” on the front-side windshield is substantiallyprevented from being affected by winds while the vehicle is moving.

As shown in FIG. 10, on the same side as the front-side valve chamber 33a along the longitudinal direction of the front-side flow path 34, thefront-side flow path 34 extends to the front-side discharge hole 33 e,and on the same side as the rear-side valve chamber 33 b along thelongitudinal direction of the rear-side flow path 35, the rear-side flowpath 35 extends to the rear-side discharge hole 33 f. More specifically,the cross-hatched areas in FIG. 10 correspond to the front-side flowpath 34 and the rear-side flow path 35. As a result, the cleaning liquid“W” from the front-side flow path 34 and the rear-side flow path 35 isdischarged to the front-side valve chamber 33 a and the rear-side valvechamber 33 b, each of which is narrower than those in the past, andtherefore, rapid diffusion of the cleaning liquid “W” into the valvechambers 33 a and 33 b is suppressed.

The front valve chamber 33 a and the rear valve chamber 33 b are eachprovided with a curved wall portion 33 g. These curved wall portions 33g are formed in front of the outlet portions of the front-side flow path34 and the rear-side flow path 35, and the cleaning liquid “W”discharged from the front-side flow path 34 and the rear-side flow path35 is rectified so as to flow along the respective curved wall portions33. In this manner, rapid diffusion of the cleaning liquid “W” into thevalve chambers 33 a and 33 b is suppressed, and turbulent flow of thecleaning liquid “W” in the valve chambers 33 a and 33 b is suppressed byrectifying the cleaning liquid “W” in the valve chambers 33 a and 33 b.

As shown in FIG. 10, the front-side flow path 34 and the rear-side flowpath 35 are different in shape from each other. However, thecross-sectional shape of each of the flow paths 34 and 35 in thedirection intersecting the longitudinal direction is formed into asubstantially rectangular shape, and the flow paths 34 and 35 are thesame in depth as each other. Note that the front-side flow path 34constitutes one flow path in the present invention, and the rear-sideflow path 35 constitutes the other flow path in the present invention.

The flow passage area of the front-side flow path 34 on the same side asthe pump chamber 32 a along the longitudinal direction is set to besmaller than the flow passage area of the front-side flow path 34 on thesame side as the front-side valve chamber 33 a along the longitudinaldirection. More specifically, as shown in FIG. 10, an outer wall portion34 a disposed on the outside of the front-side flow path 34 (i.e., onthe left side in the drawing) is provided in parallel with the side wall30 b of the housing 30, and nearer the side wall 30 b. The inner wallportion 34 b disposed on the inside of the front-side flow path 34(i.e., on the right side in the drawing) is provided on the inside ofthe side wall 30 b of the housing 30, and inclined with respect to theside wall 30 b.

As described above, the flow passage area of the inner wall portion 34 bgradually increases from the pump chamber 32 a to the front valvechamber 33 a of the front-side flow path 34. That is, the inner wallportion 34 b constitutes an inclined wall in the present invention.Furthermore, as shown in FIG. 10, the outer wall portion 34 a opposed tothe inner wall portion 34 b constitutes an opposed wall in the presentinvention.

As a result, the front-side flow path 34 is narrowed toward the pumpchamber 32 a along the longitudinal direction thereof, and the flow rateof the cleaning liquid “W” flowing from the pump chamber 32 a to thefront-side flow path 34 is increased. Therefore, the flow of thecleaning liquid “W” to the front-side valve chamber 33 a is smoothed,and rapid diffusion of the cleaning liquid “W” into the front-side valvechamber 33 a is suppressed. As described above, the front-side flow path34 is provided in order to deal with the cleaning liquid “W” to beoutputted toward the front-side windshield of the vehicle. That is, thewasher pump 20 of this embodiment employs a structure suitable for thefront-side necessary to increase the output pressure of the cleaningliquid “W”.

On the other hand, it is not necessary that the injection pressure ofthe cleaning liquid “W” on the rear-side is set to be as large as theinjection pressure of the cleaning liquid “W” on the front-side. Forthis reason, the flow passage area on the same side as the pump chamber32 a along the longitudinal direction of the rear-side flow path 35 andthe flow passage area on the same side as the rear-side valve chamber 33b along the longitudinal direction of the rear-side flow path 35 are setto be the same as each other, thereby giving priority to easilymanufactured structure of the housing 30 and the like. Specifically, asshown in FIG. 10, the lateral wall portion 35 a disposed on the outsideof the rear-side flow path 35 (on the right side in the drawing) and theinner wall portion 35 b disposed on the inside of the rear-side flowpath 35 (on the left side in the drawing) are parallel to each other,and both are parallel to the side wall 30 b of the housing 30.

Note that the flow passage area of the front-side flow path 34 on thesame side as the pump chamber 32 a is set smaller than the flow passagearea of the rear-side flow path 35 on the same side as the pump chamber32 a. On the other hand, the flow passage area of the front-side flowpath 34 on the same side as the front-side valve chamber 33 a is set tobe larger than the flow passage area of the rear-side flow path 35 onthe same side as the rear-side valve chamber 33 b. Specifically, thelength of the inner wall portion 34 b from the front-side valve chamber33 a to the pump chamber 32 a is longer than the length of the innerwall portion 35 b from the rear-side valve chamber 33 b to the pumpchamber 32 a.

As described above, by changing a pumping capacity in accordance withthe rotation of the motor 40 in the positive direction or the reversedirection, and by changing the shape of the front-side flow path 34 andthe rear-side flow path 35, the volume of the cleaning liquid “W” islarger and its flow rate is higher in the front-side flow path 34 thanin the rear-side flow path 35.

As shown in FIG. 10, a valve accommodation chamber 36 is providedbetween the front-side valve chamber 33 a and the rear-side valvechamber 33 b along the extending direction of the front-side dischargepipe 33 c and the rear-side discharge pipe 33 d. A diaphragm type valveunit 70 is mounted in the valve accommodating chamber 36. That is, thevalve unit 70 partitions it into the pair of valve chambers 33 a and 33b. The valve main body 71 b of the switching valve 71 constituting thevalve unit 70 (see FIG. 15) is disposed between the front-side dischargepipe 33 c and the rear-side discharge pipe 33 d, and movable on the sameside as the front-side discharge pipe 33 c or the rear-side dischargepipe 33 d, that is, in the extending direction of each of the dischargepipes 33 c and 33 d.

Note that the front-side discharge hole 33 e and the rear-side dischargehole 33 f are respectively disposed in the moving directions of thevalve main body 71 b of the switching valve 71, and the valve main body71 b of the switching valve 71 opens the front-side discharge pipe 33 cand closes the rear-side discharge pipe 33 d when the inner pressure ofthe front-side valve chamber 33 a becomes high. As a result, thecleaning liquid “W” flows only through the front-side discharge hole 33e, and is then jetted toward the front-side windshield. On the otherhand, the valve main body 71 b of the switching valve 71 opens therear-side discharge pipe 33 d and closes the front-side discharge pipe33 c when the inner pressure of the rear-side valve chamber 33 b becomeshigh. As a result, the cleaning liquid “W” flows only through therear-side discharge hole 33 f, and is then jetted toward the rear-sidewindshield.

Furthermore, the valve unit 70 is mounted so as to face in apredetermined direction in the valve accommodating chamber 36. That is,the valve unit 70 has an assembly direction with respect to the valveaccommodation chamber 36.

As shown in FIG. 13(a), a front-side discharge hole 33 e is opened inthe front-side valve chamber 33 a, and a first facing surface 36 a towhich one side surface 70 a (see FIG. 15) of the valve unit 70 isopposed is provided around the front-side discharge hole 33 e. Betweenthe front valve chamber 33 a and the first opposing surface 36 a, a pairof curved portions 36 b is provided for rectifying the cleaning liquid“W” flowing in the front valve chamber 33 a toward the center of thefront discharge hole 33 e, that is, the valve main body 71 b.

As shown in FIG. 13(b), a rear-side discharge hole 33 f is opened in therear-side valve chamber 33 b, and a second opposing surface 36 c, towhich the other side surface 70 b (see FIG. 15) of the valve unit 70 isopposed, is provided around the rear-side discharge hole 33 f. Notethat, between the rear-side valve chamber 33 b and the second opposingsurface 36 c, a pair of curved portions 36 d for rectifying the cleaningliquid “W” flowing in the rear-side valve chamber 33 b toward therear-side discharge hole 33 f, that is, toward the center of the valvemain body 71 b is provided.

Furthermore, the second opposing surface 36 c is provided with a pair ofrecessed portions (recessed portions) 36 e with which the erroneousassembly operation prevention protrusions 72 c (see FIG. 15) provided onthe other side surface 70 b of the valve unit 70 are engaged. Theserecessed portions 36 e are recessed toward the rear-side discharge pipe33 d (see FIG. 10). That is, each of the recessed portions 36 e isprovided to be recessed on one side of the valve body 71 in the movingdirection thereof.

Note that the recessed portions 36 e are not provided to the front-sidevalve chamber 33 a (see FIG. 13(a)). That is, with one side surface 70 aof the valve unit 70 opposed to the second opposed surface 36 c and theother side surface 70 b of the valve unit 70 opposed to the firstopposed surface 36 a, the erroneous assembly operation preventingprojection 72 c is eliminated. Therefore, the valve unit 70 protrudesfrom the valve accommodation chamber 36, and is in a state in which itis not correctly assembled, that is, in a “wrong assembled state”.

As described above, when the valve unit 70 is incorrectly assembled inthe valve accommodating chamber 36, the erroneous assembly operationprevention mechanism including the recessed portion 36 e and eacherroneous assembly operation preventing protrusion 72 c can cause thevalve unit 70 to protrude from the valve accommodating chamber 36, andconsequently, the assembler or the like to easily grasp (notify) the“incorrect assembly state” in appearance. This makes it possible toreliably prevent the valve unit 70 from being erroneously assembled inthe valve accommodation chamber 36.

Note that, as shown in FIGS. 13(a) and 13(b), the distance between thecenter of the front-side discharge hole 33 e and the rear-side dischargehole 33 f and the lower end 30 c of the second opening 30 a of thehousing 30 is set to “H”. The distance “H” is larger than the diameterdimension “D” (see FIG. 2) of the thickest portion of the front-sidedischarge pipe 33 c and the rear-side discharge pipe 33 d (H>D). As aresult, each of the discharge pipes 33 c and 33 d (each of the dischargeholes 33 e and 33 f) is disposed closer to the motor accommodatingportion 31 (upward side in the drawing) than the lower end 30 c of thehousing 30. Specifically, as shown in FIG. 4, the pair of dischargeholes 33 e and 33 f is provided closer to the motor chamber 31 a thanthe lower end of the intake pipe 32 c in the axial direction of themotor 40, and closer to the cover member CV than the upper end of thesuction pipe 32 c in the axial direction of the motor 40. This makes itpossible to reduce the height of the washer pump 20 in the axialdirection of the motor 40. Therefore, it is possible to realize thewasher pump 20 reduced in size and weight while suppressing thecomplexity of the shape of the washer pump 20.

As shown in FIGS. 14 and 15, the valve unit 70 is formed into asubstantially square plate shape. The valve unit 70 includes a switchingvalve (valve body) 71 formed by thinning a rubber material or the like,and a frame body 72 mounted on the switching valve 71 and reinforcingthe switching valve 71. In FIGS. 14(a) and 14(b), in order to clearlydistinguish the switching valve 71 from the frame 72, the frame 72 isshaded.

The switching valve 71 includes a mounting portion 71 a formed into asubstantially square shape when viewed from the moving direction of thevalve main body 71 b. The mounting portion 71 a is adapted to be mountedto the valve housing chamber 36 (see FIG. 10). Here, although not shownin detail, the mounting portion 71 a of the switching valve 71 is alsomounted on the inside of the cover member side housing portion CM (seeFIG. 3) provided in the cover member CV.

As shown in FIG. 15, the mounting portion 71 a is formed into agenerally U-shaped cross-section and a portion of the body portion 72 aof the frame 72 is mounted therein. That is, the main body portion 72 asupports the mounting portion 71 a, whereby the mounting portion 71 a isreinforced by the main body portion 72 a to prevent the mounting portion71 a from being deformed or tilted when the mounting portion 71 a ismounted to the valve accommodation chamber 36 or the like.

A valve main body 71 b formed into a substantially disk shape isprovided on the inside of the mounting portion 71 a in the radialdirection thereof. The valve main body 71 b is moved in the extendingdirection of each of the discharge pipes 33 c and 33 d in accordancewith the inner pressure of each of the valve chambers 33 a and 33 b. Asa result, the front-side discharge pipe 33 c and the rear-side dischargepipe 33 d open and close by both sides in the thickness direction of thevalve main body 71 b.

Between the valve main body 71 b and the mounting portion 71 a, anannular thin-walled portion 71 c which is deformed when the valve mainbody 71 b moves is provided. As shown in FIG. 15, the thin-walledportion 71 c is thinner than the valve main body 71 b, and has a bentcross-section. This makes it possible to easily move the valve main body71 b and to reliably open and close each of the discharge pipes 33 c and33 d.

The frame body 72 is formed of plastic or the like having a rigidityhigher than that of the switching valve 71, so that the mounting portion71 a of the switching valve 71 can be sufficiently reinforced. The framebody 72 includes a main body portion 72 a formed into a substantiallysquare shape (as viewed from the moving direction of the valve main body71 b), and part of the main body portion 72 a is mounted on the insideof the mounting portion 71 a. A circular hole 72 b having an innerdiameter substantially the same as the outer diameter of the thin-walledportion 71 c of the switching valve 71 is provided on the inside of themain body portion 72 a in the radial direction. As a result, the valvemain body 71 b is movable radially on the inside of the circular hole 72b without being hindered by the frame 72.

At the four corners of the main body portion 72 a, erroneous assemblyoperation preventing projections (convex portions) 72 c are provided,respectively. As shown in FIG. 15, these erroneous assembly operationpreventing projections 72 c project from the other side surface 70 b ofthe valve unit 70. That is, each of the erroneous assembly operationpreventing projections 72 c is provided so as to project toward one sidein the moving direction of the valve main body 71 b. Note that theoutside of the erroneous assembly operation preventing projection 72 calong the radial direction of the frame 72 is engaged with the inside ofthe recessed portion 36 e along the radial direction of the frame 72,and in the case of such an engaged relationship, the valve unit 70 is ina correctly assembled state without protruding from the valveaccommodation chamber 36.

The erroneous assembly operation preventing projections 72 c provided atthe four corners of the main body portion 72 a are disposed radiallyoutward of the circular hole 72 b, and do not hinder the movement of thevalve main body 71 b. In other words, each of the erroneous assemblyoperation preventing projections 72 c is provided in the dead space ofthe main body portion 72 a. Note that the frame body 72 cannot beassembled to the switching valve 71 so that the erroneous assemblyoperation preventing protrusions 72 c face the thin-walled portion 71 c.That is, each of the erroneous assembly operation preventing projections72 c also has an erroneous assembly operation prevention function of thevalve unit 70.

As shown in FIGS. 14(a) and 14(b), the erroneous assembly operationpreventing projection 72 c is formed into a substantially triangle shapein plan view, and has a circular hole 72 b, that is, an inclined surface72 d gradually falling toward the center of the valve main body 71 b.Note that the erroneous assembly operation preventing projections 72 care exposed at four corners (not shown) in the rear-side valve chamber33 b, respectively, with the valve unit 70 mounted in the valveaccommodation chamber 36. Therefore, by providing each of the erroneousassembly operation preventing projections 72 c with the inclined surface72 d, the rectifying effect of the cleaning liquid “W” flowing in therear-side valve chamber 33 b is not lowered. That is, each of theinclined surfaces 72 d serves to direct the orientation of the cleaningliquid “W” flowing in the rear-side valve chamber 33 b to the valve mainbody 71 b. As described above, in the erroneous assembly operationpreventing projection 72 c, the inclined surface 72 d formed on the sideof the recessed portion 36 e along the moving direction of the valvemain body 71 b guides the flow of the cleaning liquid “W” toward thecenter of the valve main body 71 b.

Note that, as shown in FIG. 15, the hardness of the movement differsdepending on the movement direction of the valve main body 71 b. Thatis, the valve main body 71 b moves in the direction of the solid arrowM1 (upward in the figure), and the movement in the direction of thedashed arrow M2 (downward in the figure) is soft. More specifically,when moving in the direction of the solid arrow M1, the movement orDeflection of the thin-walled portion 71 c is hindered by the main bodyportion 72 a, but when moving in the direction of the broken arrow M2,the movement or deformation of the thin-walled portion 71 c is nothindered by the main body portion 72 a. As a result, the hardness of themovement differs depending on the movement direction of the valve mainbody 71 b. The movement of the valve main body 71 b in the harddirection is the front-side, and the movement of the valve main body 71b in the soft direction is the rear-side. As a result, the cleaningliquid “W” is injection to the windshield on the rear-side with a weakinjection pressure, and the wide area of the windshield on the rear-sidecan be uniformly wetted with the cleaning liquid “W”.

As described above, in the washer pump 20 of this embodiment, theinjection pressure of the cleaning liquid “W” is optimized between thefront-side and the rear-side by providing a difference in injectionpressure of the cleaning liquid “W” between the front-side and therear-side. Therefore, the valve unit 70 is provided with assemblydirectionality. Therefore, four erroneous assembly operation preventingprojections 72 c are provided to the valve unit 70, and a pair ofrecessed portions 36 e is provided to the rear-side valve chamber 33 b,thereby preventing the washer pump 20 from being erroneously assembled.That is, by providing an erroneous assembling prevention mechanismcomposed of the recessed portion 36 e and the erroneous assemblyoperation preventing projection 72 c between the housing 30 and theframe 72, the yield in the assembly process of the washer pump 20 isimproved.

FIG. 16 is a cross-sectional view of the housing taken along line E-E ofFIG. 10, FIG. 17 is an enlarged partial view of the dashed circle “F” ofFIG. 10, and FIG. 18 is an enlarged partial cross-sectional view showinga modification of the porous filter.

As shown in FIGS. 1 and 2, the motor accommodating portion 31 formedinto a substantially cylindrical shape is held by a pair of tank sideretaining portions 14 provided in the washer tank 10, whereby the washerpump 20 is attached to the washer tank 10. Therefore, a dead space DShaving a substantially triangular shape is formed between the washertank 10 having a flat surface and the motor accommodating portion 31having a circular arc surface, as shown by the dashed circle in FIG. 2.A corner portion 32 e is provided in a portion of the pump accommodatingportion 32, which corresponds to the dead space DS. That is, the cornerportion 32 e is disposed in the housing 30 between the motoraccommodating portion 31 and the washer tank 10 with the washer pump 20mounted on the washer tank 10.

As shown in FIGS. 16 and 17, a respiratory hole 80 is provided betweenthe motor accommodating portion 31 and the corner portion 32 e tocommunicate the inside of the motor accommodating portion 31 with itsoutside. More specifically, one end side (lower side in FIG. 16) of thebreathing hole 80 opens to the inside of the motor accommodating portion31, and the other end side (upper side in FIG. 16) of the breathing hole80 opens to the inside of the corner portion 32 e. As a result, therespiratory hole 80 communicates the motor chamber 31 a in the motoraccommodating portion 31 with the outside of the housing 30. Therespiratory hole 80 is disposed in the corner portion 32 e located inthe dead space DS (see FIG. 2) of the pump housing portion 32, but isnot in communication with the pump chamber 32 a.

The respiratory hole 80 extends in the axial direction of the motoraccommodating portion 31, and is formed into a stepped shape, as shownin a partially enlarged view within the dashed circle of FIG. 16. Thus,air (AIR) can flow between the corner portion 32 e (outside the housing30) outside the motor accommodating portion 31 and in the dead space DSof the pump accommodating portion 32 and the motor chamber 31 a in themotor accommodating portion 31.

Note that the air in the motor accommodating portion 31 is expanded bythe heat generated when the motor 40 is operated. Therefore, in order toproperly operate the motor 40, a “respiratory structure” for moving air(AIR) between the motor chamber 31 a in the motor accommodating portion31 and the outside of the housing 30 is required. However, in order toprovide this respiratory structure, when a housing of a dedicated designhaving only a breathing hole is used, the housing may become larger insize. Therefore, in the washer pump 20 of this embodiment, therespiratory hole 80 is arranged in the corner portion 32 e of thehousing 30, which may be the dead space DS as described above.

Therefore, the housing 30 does not become unnecessarily large, and asufficient respiratory function can be provided. Furthermore, it ispossible to arrange the respiratory hole 80 within the outer rangeincluding the washer pump 20 and the washer tank 10 with the washer pump20 attached to the washer tank 10.

As shown in FIGS. 10, 16, and 17, a porous filter 81 configured toregulate the passage of water and to allow the passage of air is mountedon the same side of the respiratory hole 80 as the second opening 30 a.The porous filter 81 is disposed so as to close the respiratory hole 80,and the outer peripheral portion thereof is fixed to the inside of thecorner portion 32 e (housing 30) by ultrasonic welding or the like. Onthe other hand, instead of ultrasonic welding, the outer peripheralportion thereof may be fixed to the inside of the corner portion 32 e(housing 30) by using double-sided tape, adhesive, or the like.

As shown in FIGS. 10 and 17, on the outside of the pump chamber 32 a andupstream side (outside of the housing 30) of the porous filter 81provided in the respiratory hole 80, the housing 30 is provided with afirst ventilation passage 82 that extends throughout the housing 30 thewidth direction along the extending direction of each of the dischargetubes 33 c and 33 d. That is, the first ventilation passage 82 isprovided so as to extend in the width direction of the housing 30crossing the intake direction (vertical direction in FIG. 17) of thecleaning liquid “W”, and one end side (right side in FIG. 17) of thefirst ventilation passage 82 communicates with the other end side of therespiratory hole 80.

The first air passage 82 is formed between the arc-shaped wall 30 d ofthe housing 30 forming the pump chamber 32 a, the outer wall 30 e of thehousing 30 provided on the outside of the arc-shaped wall 30 d in theradial direction, and the cover member CV (see FIG. 3). That is, part ofthe inside of the corner portion 32 e, the porous filter 81 provided onthe inside of the corner portion 32 e so as to block the respiratoryhole 80, and the first ventilation passage 82 are each covered by acover member CV which blocks the second opening 30 a of the housing 30.As a result, the respiratory hole 80, the porous filter 81, and thefirst ventilation passage 82 cannot be seen from the axial direction ofthe armature shaft 44, and hidden by the cover member CV, as shown inFIG. 3.

Furthermore, a cut-out portion 30 f formed by partially cutting theouter wall 30 e is disposed on the other side (left side in FIG. 17) ofthe width direction of the housing 30 that intersects the intakedirection of the cleaning liquid “W”. As a result, air (AIR) flowsbetween the outside of the housing 30 and the respiratory hole 80 viathe first ventilation passage 82, as indicated by the dashed arrow inthe drawing. In other words, the respiratory holes 80, i.e., the porousfilter 81, are disposed in a deep portion covered with the cover memberCV along the width direction of the housing 30.

As described above, by providing the first ventilation passage 82surrounded by the arc-shaped wall 30 d, the outer wall 30 e, and thecover member CV upstream of the respiratory hole 80, the distancebetween the outside of the housing 30 and the porous filter 81 isincreased, thereby making it difficult for rainwater, dust, and the liketo reach the porous filter 81. Accordingly, sufficient respiratoryfunction is maintained for a long period of time, and the life of thewasher pump 20 can be extended.

In the washer pump 20 of this embodiment, a second ventilation passage83 is provided further upstream of the first air passage 82. Morespecifically, as shown in FIG. 17, the second ventilation passage 83 isconnected to the first ventilation passage 82 at the corner 32 e on theopposite from the respiratory hole 80 with respect to the suction pipe32 c. The second ventilation passage 83 is formed so as to be foldedback to the first ventilation passage 82, and one end thereofcommunicates with the other end of the first ventilation passage 82 viathe notch portion 30 f. Like the first ventilation passage 82, thesecond ventilation passage 83 is provided so as to extend oversubstantially the entire area in the width direction of the housing 30that intersects the intake direction of the cleaning liquid “W”.

However, the second ventilation passage 83 is not closed by the covermember CV, and as shown in FIGS. 3 and 17, the entire width direction ofthe housing 30 crossing the intake direction of the cleaning liquid “W”of the second ventilation passage 83 is opened. That is, part of theinside of the corner portion 32 e is covered with the cover member CV.As a result, even if the washer pump 20 is accidentally exposed towater, it is difficult to form a water film or the like because thesecond ventilation passage 83 is elongated and opened to a large extent,and therefore, it is effectively suppressed that moisture or the likedisturbs the respiratory operation.

Instead of the porous filter 81 fixed to the inside of the cornerportion 32 e by ultrasonic welding or the like, a filter member 90 asshown in FIG. 18 may be detachably provided in the respiratory hole 80.As a result, the filter member 90 can be periodically replaced, and thewasher pump 20 is improved in maintainability. Specifically, the filtermember 90 is composed of: a pipe member 91 made of rubber or the like,and a porous filter 92 fixed to one end in the axial direction of thepipe member 91 by ultrasonic welding or the like.

Next, the operation of the washer pump 20 formed as described above, inparticular, the flow of the cleaning liquid “W” inside the housing 30will be described in detail for each of the front-side flow path and therear-side flow path.

FIG. 19 is an explanatory view for explaining the flow of the cleaningliquid in the front-side flow path, and FIG. 20 is an explanatory viewfor explaining the flow of the cleaning liquid in the rear-side flowpath.

[Regarding Front-Side]

When the armature shaft 44 of the motor 40 is driven so as to rotate inthe counterclockwise direction by operating an operation switch (notshown), the impeller 60 is rotated in the direction of the solid arrowR1 as shown in FIG. 19. Then, the cleaning liquid “W” in the washer tank10 is sucked into the pump chamber 32 a through the cleaning liquidinflow hole 32 b. Then, the cleaning liquid “W” in the pump chamber 32 aflows into the front-side flow path 34.

Note that, at the time of rotating the impeller 60 in thecounterclockwise direction, since the pumping capacity is higher thanthat at the time of rotating it in the clockwise direction, the flowrate of the cleaning liquid “W” flowing into the front-side flow path 34is increased as shown by a solid line arrow in white in the drawing. Theflow rate of the cleaning liquid “W” flowing through the front-side flowpath 34 is higher than that of the cleaning liquid “W” flowing throughthe rear-side flow path 35.

Then, the cleaning liquid “W” having a high flow rate flowing throughthe front-side flow path 34 is discharged into the front-side valvechamber 33 a (shaded portion in the figure). At this time, the flowspeed of the cleaning liquid “W” is high, the cleaning liquid “W” isdischarged into the front-side valve chamber 33 a at the front-sidedischarge hole 33 e, and immediately after being discharged into thefront-side valve chamber 33 a, the cleaning liquid “W” is rectified byfollowing the curved wall portion 33 g, so that the cleaning liquid “W”does not become turbulent in the front-side valve chamber 33 a.Therefore, the cleaning liquid “W” discharged into the front-side valvechamber 33 a is smoothly collected toward the center of the valve unit70, that is, toward the valve main body 71 b of the switching valve 71.

As a result, the inner pressure of the front-side valve chamber 33 a isincreased, the valve main body 71 b is moved in the direction indicatedby the solid arrow M1 in FIGS. 15 and 19, and the front-side dischargehole 33 e is opened. Then, the cleaning liquid “W” is injectedvigorously toward a predetermined injection point of the front-sidewindshield. At this time, the rear-side discharge hole 33 f of therear-side discharge pipe 33 d is closed by the valve main body 71 b.

[Regarding Rear-Side]

When the armature shaft 44 of the motor 40 is driven to rotate in theclockwise direction by operating the operation switch, as shown in FIG.20, the impeller 60 is rotated in the direction of the dashed arrow R2.Then, the cleaning liquid “W” in the washer tank 10 is sucked into thepump chamber 32 a through the cleaning liquid inflow hole 32 b. Then,the cleaning liquid “W” in the pump chamber 32 a flows into therear-side flow path 35.

Note that, since the pumping capacity corresponding to the rotation ofthe impeller 60 in the clockwise direction is lower than the pumpingcapacity corresponding to the rotation of the impeller 60 in thecounterclockwise direction, the quantity of the cleaning liquid “W”flowing into the rear-side flow path 35 is small as shown by theoutlined dashed arrow in the drawing. The flow rate of the cleaningliquid “W” flowing through the rear-side flow path 35 is lower than thatof the cleaning liquid “W” flowing through the front-side flow path 34.

Then, the cleaning liquid “W” flowing through the rear-side flow path 35is discharged into the rear-side valve chamber 33 b (shaded portion inthe figure). At this time, the cleaning liquid “W” is discharged intothe rear-side valve chamber 33 b at the rear-side discharge hole 33 f,and immediately after being discharged into the rear-side valve chamber33 b, the cleaning liquid “W” is rectified along the curved wall portion33 g, so that the cleaning liquid “W” does not become turbulent in therear-side valve chamber 33 b. Therefore, the cleaning liquid “W”discharged into the rear-side valve chamber 33 b is smoothly collectedtoward the center of the valve unit 70, that is, toward the valve mainbody 71 b of the switching valve 71.

As a result, the inner pressure of the rear-side valve chamber 33 b isincreased, the valve main body 71 b is moved in the direction indicatedby the dashed arrow M2 in FIGS. 15 and 20, and the rear-side dischargehole 33 f is opened. Then, the cleaning liquid “W” is jetted toward apredetermined jetting point of the windshield on the rear-side. At thistime, the front-side discharge hole 33 e of the front-side dischargepipe 33 c is closed by the valve main body 71 b.

As described above in detail, according to the washer pump 20 of thisembodiment, since the pump chamber 32 a, the valve chambers 33 a and 33b, the discharge holes 33 e and 33 f, and the flow paths 34 and 35 areintegrally provided in the housing 30, respectively, in the case wherethese are formed of separate members, a step or the like that inhibitsthe flow of the cleaning liquid “W” does not need to be formed in theflow path of the cleaning liquid “W”, so that the pressure loss of thecleaning liquid “W” can be reduced.

In addition, since the valve chambers 33 a and 33 b of the flow paths 34and 35 extend to the discharge holes 33 e and 33 f, the cleaning liquid“W” flowing out of the flow paths 34 and 35 can be discharged at aportion closer to the central of the valve chambers 33 a and 33 b thanbefore. As a result, the outlet portions of the flow paths 34 and 35 andthe inlet portions of the discharge holes 33 e and 33 f can be broughtcloser to each other, and the turbulent of the cleaning liquid “W” inthe valve chambers 33 a and 33 b can be suppressed, thereby reducing thepressure loss.

Therefore, the lowering of the injection capability is suppressed, andin the washer pump having the same injection capability as in the past,it is possible to adopt a small motor having a low output, and it ispossible to realize further size and weight reduction of the washerpump.

Furthermore, according to the washer pump 20 of this embodiment, sincethe flow passage area of the front-side flow path 34 on the same side asthe pump chamber 32 a is smaller than the flow passage area of thefront-side valve chamber 33 a, the flow rate of the cleaning liquid “W”flowing through the front-side flow path 34 is increased, the flow ofthe cleaning liquid “W” into the front-side valve chamber 33 a issmoothed, and rapid diffusion of the cleaning liquid “W” into thefront-side valve chamber 33 a can be suppressed. Therefore, turbulent ofthe cleaning liquid “W” in the valve chambers 33 a and 33 b can besuppressed more reliably.

Furthermore, according to the washer pump 20 of this embodiment, sincethe front-side flow path 34 includes the inner wall portion 34 b thatgradually increases the flow passage area from the pump chamber 32 atoward the front-side valve chamber 33 a, the flow passage area of thefront-side flow path 34 can be changed linearly from the pump chamber 32a toward the front-side valve chamber 33 a. Therefore, the turbulentflow in the front-side flow path 34 is suppressed more reliably, and thewasher pump 20 with further pressure loss and high efficiency isrealized.

In addition, according to the washer pump 20 of this embodiment, sincethe front-side flow path 34 has an outer wall portion 34 a facing theinner wall portion 34 b, the outer wall portion 34 a is provided nearthe side wall 30 b of the housing 30 in parallel with the side wall 30b, and the inner wall portion 34 b is provided on the inside of thehousing 30, the front-side flow path 34 in which the flow passage areagradually increases from the pump chamber 32 a toward the front-sidevalve chamber 33 a can be formed on the inside of the housing 30 withoutincreasing the size of the housing 30. Therefore, the dedicated designof the cover member CV is unnecessary, and the increase in cost issuppressed.

Furthermore, according to the washer pump 20 of this embodiment, sincethe flow passage area of the front-side flow path 34 in the pump chamber32 a is smaller than the flow passage area of the pump chamber 32 a ofthe rear-side flow path 35, it is possible to make the pump capacitydifferent according to the rotation of the motor 40 in the positivedirection or the reverse direction.

Furthermore, since the front-side flow path 34 is provided in order todeal with the cleaning liquid “W” to be outputted toward the front-sidewindshield of the vehicle, it is possible to substantially maintain thetarget position of the cleaning liquid “W” on the front-side windshieldwithout being affected by winds. That is, the cleaning performance ofthe washer pump 20 is improved.

Furthermore, according to the washer pump 20 of this embodiment, thehousing 30 is provided with: a motor accommodating portion 31 foraccommodating the motor 40; and a corner portion 32 e disposed betweenthe motor accommodating portion 31 and the washer tank 10, and therespiratory hole 80 for communicating the inside of the motoraccommodating portion 31 with its outside is provided between the motoraccommodating portion 31 and the corner portion 32 e. As a result, withthe washer pump 20 attached to the washer tank 10, it is possible toarrange the respiratory hole 80 within the range of its outlineincluding the washer pump 20 and the washer tank 10. Therefore, it ispossible to prevent the respiratory structure from being damaged at thetime of installation or the like, and it becomes unnecessary to use amember for the breathing structure, which is used in the past, and itbecomes possible to achieve a further reduction in size and weight.

Furthermore, according to the washer pump 20 of this embodiment, one endside of the respiratory hole 80 is opened inside the motor accommodatingportion 31, the other end side of the breathing hole 80 is opened insidethe corner portion 32 e, and the inside of the corner portion 32 e iscommunicated with the outside, and the corner portion 32 e is partiallycovered with a cover member CV that closes the second opening 30 aformed on the same side as breathing hole 80 of the housing 30. Thismakes it difficult for rainwater, dust, and the like to reach the porousfilter 81, so that a sufficient respiratory function can be maintainedfor a long period of time, and the life of the washer pump 20 can beextended.

Furthermore, according to the washer pump 20 of this embodiment, sincethe porous filter 81 is provided in the respiratory hole 80 to regulatethe passage of water while allowing the passage of air, it is possibleto reliably prevent the entry of rainwater or the like into the motorchamber 31 a.

Furthermore, according to the washer pump 20 of this embodiment, sincethe porous filter 81 is provided on the inside of the corner portion 32e, and covered with the cover member CV which closes the second opening30 a formed on same side as the respiratory hole 80 of the housing 30,rainwater or the like can be hardly reached to the porous filter 81.Therefore, the porous filter 81 can be kept clean for a long period oftime, and the maintenance cycle can be extended.

Furthermore, according to the washer pump 20 of this embodiment, sinceone end side of the respiratory hole 80 is opened inside the motoraccommodating portion 31, the other end side of the breathing hole 80 isopened inside the corner portion 32 e, the first ventilation passage 82communicating with the other end side of the breathing hole 80 isprovided, and the first ventilation passage 82 is covered with the covermember CV which closes the housing 30, rainwater or the like can be madeharder to reach the porous filter 81.

Furthermore, according to the washer pump 20 of this embodiment, sincethe first ventilation path 82 extends in the width direction of thehousing 30 intersecting with the intake direction of the cleaning liquid“W”, the distance of the first ventilation path 82 can be increased, andrainwater or the like can be made harder to reach the porous filter 81.

Furthermore, according to the washer pump 20 of this embodiment, one endside of the first ventilation passage 82 communicates with therespiratory hole 80, the other end side of the first ventilation passage82 communicates with the second ventilation passage 83 provided in thehousing 30, the second ventilation passage 83 extends in the widthdirection of the housing 30, and is not covered by the cover member CV,so that the second ventilation passage 83 can be opened slender andlarge, making it difficult to form a water membrane or the like, andrainwater or the like can be made more difficult to reach the porousfilter 81.

In addition, according to the washer pump 20 of this embodiment, anerroneous assembly operation prevention mechanism is provided betweenthe housing 30 and the frame body 72, and composed of: a recess portion36 e and an erroneous assembly operation preventing projection 72 c fornotifying erroneous assembly of the valve unit 70 with respect to thehousing 30 by causing the switching valve 71 to protrude from thehousing 30.

As a result, when the valve unit 70 is incorrectly assembled to thehousing 30, the valve unit 70 protrudes from the housing 30, and thecover member CV that closes the housing 30 cannot be attached to thehousing 30. In other words, the washer pump 20 is not physicallyassembled, so that erroneous assembly of the valve unit 70 with respectto the housing 30 is reliably prevented. Therefore, the process yield ofthe washer pump 20 is improved, and the reliability of the product isimproved.

Furthermore, according to the washer pump 20 of this embodiment, theerroneous assembly operation prevention mechanism is formed by arecessed portion 36 e provided in the housing 30 and recessed on oneside in the moving direction of the valve main body 71 b (the switchingvalve 71), and an erroneous assembly operation preventing projection 72c provided in the frame body 72 and projecting on one side in the movingdirection of the valve main body 71 b and engaged with the recessedportion 36 e. Therefore, the assembler or the like can easily visuallyconfirm the recessed portion 36 e and the erroneous assembly operationpreventing projection 72 c, and can more reliably prevent the valve unit70 from being erroneously assembled to the housing 30.

According to the washer pump 20 of this embodiment, the frame body 72 isformed into a rectangular shape (as viewed from the moving direction ofthe valve main body 71 b), the erroneous assembly operation preventingprojections 72 c are respectively provided at the four corners of theframe body 72, and the outside of the erroneous assembly operationpreventing projections 72 c along the radial direction of the frame body72 is engaged with the inside of the recessed portion 36 e along theradial direction of the frame body 72. Therefore, the center position ofthe valve main body 71 b and the center positions of the front-sidedischarge pipe 33 c and the rear-side discharge pipe 33 d can beaccurately positioned without shifting. Therefore, it is possible tosuppress variation in the movement characteristic of the valve main body71 b (valve opening characteristic/valve closing characteristic) foreach product. In addition, since the erroneous assembly operationpreventing projections 72 c are provided at the four corners of theframe body 72, when the valve unit 70 is assembled to the housing 30,any one of the four sides formed by the outer periphery of the mountingportion 71 a of the switching valve 71 can be inserted toward thehousing 30, and the insertion direction of the valve unit 70 is notlimited.

Furthermore, according to the washer pump 20 of this embodiment, theerroneous assembly operation preventing projection 72 c is formed withan inclined surface 72 d for guiding the flow of the cleaning liquid “W”toward the center of the switching valve 71 (i.e., the valve main body71 b) on the same side as the recessed portion 36 e along the movingdirection of the valve main body 71 b. As a result, the flow of thecleaning liquid “W” can be smoothed, and the efficiency of the washerpump 20 is improved.

Furthermore, according to the washer pump 20 of this embodiment, sincethe frame body 72 is higher in rigidity than the switching valve 71, itis possible to prevent the valve unit 70 from being forcibly erroneouslyassembled to the housing 30 in advance, and it is possible to reliablyprevent the valve unit 70 from being erroneously assembled to thehousing 30.

Furthermore, according to the washer pump 20 of this embodiment, sincethe motor chamber 31 a, the pump chamber 32 a, the valve chambers 33 aand 33 b, and the discharge holes 33 e and 33 f are integrally providedin the housing 30, it is unnecessary to prepare the valve unit as adiscrete component to the housing as in the past. Therefore, it ispossible to cope with the size and weight reduction and multifunctionwithout incurring any increase in size and cost. In addition, it ispossible to eliminate a decrease in the flow rate of the liquid causedby a decrease in the connection accuracy, and it is possible to reliablysuppress a decrease in the injection capability of the liquid, and thelike.

In addition, according to the washer pump 20 of this embodiment, themotor 40 includes: a yoke 41 fixed to the inside of the motor chamber 31a; two magnets 42 fixed to the inside of the yoke 41, a commutator 45fixed to the armature shaft 44 and having six segments 45 a, and anarmature core 43 fixed to the armature shaft 44 and having six slots 43a around which coils 46 are wound by overlapping winding, and rotated onthe inside of the magnet 42.

Therefore, even if the armature core 43 is reduced in diameter, the coil46 can be easily attached to the armature core 43 by the double flyermethod in three winding works. Furthermore, compared with a motor usingone magnet in a ring shape, by using two magnets obtained by dividingthe magnet, it is possible to improve the layout property at the time offixing the magnet in addition to downsizing of the magnet. Therefore, itis possible to cope with the downsizing and weight reduction of themotor 40 while suppressing the manufacturing cost.

Furthermore, according to the washer pump 20 of this embodiment, themotor 40 includes a power feeding brush 54 slidably contacted to thecommutator 45, and a retaining plate 53 that holds the power feedingbrush 54 by the brush retaining portion 53 b, and two bent portions 53 care provided near the base end portion 53 a of the retaining plate 53.

As a result, the mobile range of the retaining plate 53 can be widened,and the power feeding brush 54 can be brought into sliding contact withthe commutator 45 with an optimal pressing force. In addition, since thepower supply brush 54 can be used up to the last, the size of the powersupply brush 54 can be reduced, and the power supply brush 54 can beeasily arranged in a space-saving manner.

Furthermore, according to the washer pump 20 of this embodiment, themotor chamber 31 a is closed by the motor cover 50, the connectorconnection portion 52 to which the power supply connector is connectedis provided on the outside of the motor cover 50, the rib 55 is providedon the inside of the motor cover 50, and the base end portion 53 a ofthe retaining plate 53 is mounted.

Accordingly, even if the cover main body 51 is reduced in thickness, thecover main body 51 has sufficient intensity, and sufficiently withstandthe integrating of the connector connecting portion 52 and the rigidfixation of the base end portion 53 a of the retaining plate 53.

Furthermore, according to the washer pump 20 of this embodiment, theimpeller 60 is provided with a bowl-shaped convex portion 62 a, and thepump chamber 32 a is provided with a bowl-shaped recess 32 d extendingalong the bowl-shaped convex portion 62 a of the impeller 60.

As a result, the clearance between the pump chamber 32 a and theimpeller 60 can be reduced to improve the pump efficiency, therebypreventing the pump capacity from deteriorating. Therefore, the washerpump 20 can be made smaller and lighter.

Furthermore, according to the washer pump 20 according to thisembodiment, a pair of reinforcing ribs 31 c is formed on the outercircumference portion of the motor accommodating portion 31 (housing 30)that are fitted to each tank side retaining portion 14 provided in thewasher tank 10.

This makes it possible to mount the washer pump 20 in a washer tank inwhich an old-type washer pump is mounted while reinforcing the motoraccommodating portion 31 in response to downsizing of the motoraccommodating portion 31. That is, for example, during maintenance ofthe washer apparatus, the washer pump 20 can be simply employed in placeof the old-type washer pump.

Furthermore, according to the washer pump 20 of this embodiment, a pairof discharge holes 33 e and 33 f is provided closer to the motor chamber31 a than the second opening 30 a of each of the valve chambers 33 a and33 b.

As a result, since the pair of discharge holes 33 e and 33 f is providedbetween the lower end and the upper end of the suction pipe 32 c, theheight of the washer pump 20 in the axial direction of the motor 40 canbe reduced. Therefore, it is possible to realize a reduction in size andweight of the washer pump 20 while suppressing the complexity of theshape of the washer pump 20.

It is needless to say that the present invention is not limited to theabove-mentioned embodiments, and various modifications can be madewithout departing from the scope of the present invention. For example,in the above embodiment, the shape of the front-side flow path 34 andthe shape of the rear-side flow path 35 are different from each other,but the present invention is not limited to this, and the front-sideflow path and the rear-side flow path may have the same shape accordingto the specification of the washer pump 20 or the like.

In the above embodiment, the inner wall portion 34 b of the front-sidepassage area wall, and the flow passage area of the front-side flow path34 is changed linearly, but the present invention is not limited tothis, and the flow passage area of the front-side flow path 34 may bechanged stepwise by forming the inner wall portion 34 b in a stepwisemanner in accordance with the specification of the washer pump 20 or thelike.

Furthermore, in the above embodiment, although the washer pump 20 isshown as the one in which the cleaning liquid “W” is jetted to thefront-side windshield and the windshield on the rear-side of thevehicle, the present invention is not limited to this, and can beapplied to, for example, a washer pump in which the cleaning liquid “W”is jetted to the forward side and the return side of the wiper blade inthe wiping direction.

In addition, material, shape, dimension, number, installation place, andthe like of each component in the above embodiment are arbitrary as longas the present invention can be achieved, and are not limited to theabove embodiment.

The washer pump is used for sucking the cleaning liquid stored in thewasher tank, jetting the cleaning liquid to the windshield, and removingdirt such as dust attached to the windshield.

While the present disclosure has been illustrated and described withrespect to a particular embodiment thereof, it should be appreciated bythose of ordinary skill in the art that various modifications to thisdisclosure may be made without departing from the spirit and scope ofthe present disclosure.

1. A washer pump configured to suck liquid stored in a tank andconfigured to jet the liquid to a surface to be cleaned, comprising: amotor that rotates in forward and reverse directions; an impeller thatis rotated by the motor; a pump chamber in which the impeller is housed;a pair of valve chambers in which the liquid flows in response to therotation direction of the impeller; a changeover valve for partitioningthe pair of valve chambers, a pair of discharge holes provided on bothsides of the switching valve in the moving direction; and a pair of flowpaths provided between the pump chamber and the pair of valve chambers,wherein the pump chamber, the valve chamber, the discharge hole, and theflow paths are integrally provided to each other in the housing, and theflow paths extend to the discharge hole on the same side as the valvechamber.
 2. The washer pump according to claim 1, wherein the flowpassage area on the same side as the pump chamber of at least one of theflow paths is smaller than the flow passage area on the same side as thevalve chamber.
 3. The washer pump according to claim 2, wherein one ofthe flow paths has an inclined wall that gradually increases a flowpassage area from the same side as the pump chamber toward the same sideas the valve chamber.
 4. The washer pump according to claim 3, whereinone of the flow path has an opposing wall facing the inclined wall, theopposing wall is disposed parallel to the side wall of the housing nearthe side wall, the inclined wall is provided on the inside of the sidewall of the housing.
 5. The washer pump according to claim 2, whereinthe flow passage area of one of the flow path on the same side as thepump chamber is smaller than the flow passage area of the other of theflow paths on the same side as the pump chamber.
 6. The washer pumpaccording to claim 2, wherein one of the flow paths is providedcorresponding to the injection of the liquid onto the surface on thefront-side of the vehicle.